Embodiments of the invention generally relate to a substrate support.
Thin film transistors (TFTs) are conventionally made on large glass substrates or plates for use in monitors, flat panel displays, solar cells, personal digital assistants (PDAs), cell phones and the like. TFTs are made in a cluster tool by sequential deposition of various films including amorphous silicon, doped and undoped silicon oxides, silicon nitride and the like in a plurality of vacuum process chambers typically arranged around a central transfer chamber. The cluster tool is typically coupled to a factory interface that includes a plurality of substrate storage cassette that holds: substrates before and after processing. A load lock chamber is generally disposed between the factory interface and cluster tool to facilitate substrate transfer between a vacuum environment of the cluster tool and an atmospheric environment of a factory interface.
The positioning of glass substrates used for displays in a load lock chamber is difficult as compared to smaller, 200 mm and even 300 mm circular substrates. For example, as glass substrates often have dimensions exceeding 550 mm by 650 mm, with trends towards 1.2 square meters and larger, small deviations in position may result in significant substrate misalignment. A misaligned substrate has high probability of damage, resulting in a costly loss of the substrate. Moreover, a misaligned substrate must be manually removed from the load lock chamber, thereby requiring costly loss of production time and diminished substrate throughput.
Typically, the accuracy of substrate placement is controlled by a robot disposed in the factory interface that is utilized to move substrate""s between the cassettes and the load lock. However, many end-users of cluster tools are now providing the factory interface and robot disposed therein. Thus, if the accuracy and repeatability of substrate placement by the user supplied robot is not within the designed specifications of the load lock chamber, substrate damage is likely. It would be desirable for the load lock chamber to be more compatible with regard to substrate placement so that tool components (i.e., user provided factory interfaces) may be used in order to reduce system costs while increasing design flexibility.
Therefore, there is a need for a load lock and substrate support that corrects the orientation and position of substrates placed thereon.
A method and apparatus for supporting a substrate placed on a substrate support is generally provided. In one embodiment, an apparatus for supporting a substrate includes a support plate having a first body disposed proximate thereto. A first pushing member is radially coupled to the first body and adapted to urge the substrate in a first direction parallel to the support plate when the first body rotates.
In another embodiment, an apparatus for supporting a substrate includes a plurality of pushing members, each having a first rotational axis and a second rotational axis orientated perpendicular to the first rotational axis. A first pushing member is adapted to urge the substrate in a first direction, a second pushing member is adapted to urge the substrate in a second direction that is opposite the first direction, a third pushing member is adapted to urge the substrate in a third direction, and a fourth pushing member is adapted to urge the substrate in a fourth direction that is opposite the third direction.
In another aspect, a load lock chamber having a substrate support that supports a substrate is provided. In one embodiment, the load lock chamber includes a chamber body having a substrate support plate disposed therein. A first body disposed is proximate to the support plate. A first pushing member is radially coupled to the first body and adapted to urge the substrate in a first direction parallel to the support plate when the first body rotates.
In yet another aspect, a method for aligning a substrate is provided. In one embodiment, a method for aligning a substrate on a substrate support includes placing a substrate on a support, elevating a cooling plate towards the support to actuate an alignment mechanism, and moving a first pushing member of the alignment mechanism towards a center of the support plate in response to the actuation to urge the substrate in a first direction.
In another embodiment, a method for aligning a substrate on a substrate support includes placing a substrate on a support, rotating a first pushing member to urge the substrate in a first direction, rotating a second pushing member to urge the substrate in a second direction different than the first direction.